We have been studing the mechanism of lipid accumulation in smooth muscle cells of muscular arteries in diabetes. Initial studies showed that excess accumulation of lipid in arteries of diabetic rats was related to high concentrations of FFA in plasma. Recent electron microscopic findings in normal rats showed that intravenous infusion of triacylglycerol caused deposition of lipid in myocytes of the dorsal pedal artery. They also showed that lipoprotein lipase activity is involved in uptake of plasma triacylglycerol by muscular arteries. Biochemical studies are under way to determine factors regulating lipoprotein lipase activity and deposition of lipid in muscular arteries.